CR
Chatham Islands Shag Leucocarbo onslowi



Taxonomy

Taxonomic note
Following Kennedy and Spencer (2014) the genus Phalacrocorax has been divided into six genera, with P. magellanicus, P. bougainvilliorum, P. atriceps, P. verrucosus, P. carunculatus, P. chalconotus, P. onslowi, P. campbelli, P. ranfurlyi and P. colensoi moved into Leucocarbo (HBW and BirdLife International 2018).

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
Handbook of the Birds of the World and BirdLife International. 2018. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 3. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v3_Nov18.zip.
Kennedy, Martyn & Spencer, Hamish. 2014. Classification of the Cormorants of the World. Molecular phylogenetics and evolution. 79: 249-257.
Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
A2bcde+3bcde+4bcde A2bcde+3bcde+4bcde; B2ab(ii,iii,iv,v); C2a(ii) A2bcde+3bcde+4bcde; B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v); C2a(i,ii); D1+2

Red List history
Year Category Criteria
2018 Critically Endangered A2bcde+3bcde+4bcde
2016 Critically Endangered A2bcde+3bcde+4bcde
2012 Critically Endangered B2ab(ii,iii,iv,v)
2010 Critically Endangered B2a+b(ii,iii,iv,v)
2009 Critically Endangered B2a+b(ii,iii,iv,v)
2008 Critically Endangered
2007 Critically Endangered
2005 Critically Endangered
2004 Endangered
2000 Endangered
1996 Vulnerable
1994 Vulnerable
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency does not normally occur in forest
Land-mass type Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 8,600 km2 poor
Area of Occupancy (breeding/resident) 1 km2 good
Number of locations 2 -
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 710 mature individuals good estimated 2011
Population trend decreasing poor suspected 2006-2030
Rate of change over the past 10 years/3 generations (longer of the two periods) 90-99% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 90-99% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 90-99% - - -
Generation length 8.7 years - - -
Number of subpopulations 1 - - -
Percentage of mature individuals in largest subpopulation 100% - - -

Population justification: A census carried out in 2011 counted 355 breeding pairs (Debski et al. 2012), presumably equating to 714 mature individuals and c.1,070 individuals in total.

Trend justification:  Debski et al. (2012) estimated a 58% decline from 1997 to 2012. 


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
New Zealand extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
New Zealand Chatham Islands (nearshore)
New Zealand Main Chatham
New Zealand Mangere
New Zealand Rangiauria Pitt Island
New Zealand Star Keys Motuhope
New Zealand Tuku

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Sea Cliffs and Rocky Offshore Islands major breeding
Marine Intertidal Rocky Shoreline major breeding
Marine Intertidal Tidepools major breeding
Marine Neritic Macroalgal/Kelp major resident
Marine Neritic Pelagic suitable resident
Marine Neritic Seagrass (Submerged) major resident
Marine Neritic Subtidal Loose Rock/pebble/gravel major resident
Marine Neritic Subtidal Rock and Rocky Reefs major resident
Marine Neritic Subtidal Sandy major resident
Marine Neritic Subtidal Sandy-Mud major resident
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Biological resource use Hunting & trapping terrestrial animals - Persecution/control Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Future Whole (>90%) Unknown Unknown
Stresses
Indirect ecosystem effects, Ecosystem degradation
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species disturbance, Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Bos taurus Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Canis familiaris Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Felis catus Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Gallirallus australis Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Ovis aries Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Sus domesticus Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Trichosurus vulpecula Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Arctocephalus forsteri Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success

Utilisation
Purpose Scale
Pets/display animals, horticulture international

Recommended citation
BirdLife International (2024) Species factsheet: Chatham Islands Shag Leucocarbo onslowi. Downloaded from https://datazone.birdlife.org/species/factsheet/chatham-islands-shag-leucocarbo-onslowi on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.